Automatic latch



Oct. 12, 1965 J, BROWN 3,211,479

AUTOMATIC LATCH Filed April 23, 1962 1.105 B. BZOLU/V INVENTOR.

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AT TOR/V5 Y United States Patent '0 3,211,479 AUTOMATIC LATCH Joe R. Brown, Houston, Tex., assignor to Cicero C. Brown, Houston, Tex. Filed Apr. 23, 1962, Ser. No. 189,622 7 Claims. (Cl. 28536l)) This invention relates to an automatic latch and more particularly to an automatic bayonet-type latch for releasably securing a pipe in a cylindrical socket.

Generally speaking, the present invention is directed to a form of automatic latching device by which a tubular body, such as a pipe, may be releasably coupled to another body without rotating the tubular body itself.

In equipping oil and gas wells, for example, it is frequently necessary to run a pipe string into the well bore and to couple it to another structure already in place deep in the well. Commonly, this is done by simply screwing the pipe into a threaded socket provided in the structure already in place or by means of a conventional bayonet or ]-type coupling in which the pipe is rotated through at least a part of a rotation to engage a pin in a suitably shaped slot. In all such conventional couplings or connecting elements, it will be evident that it is necessary to rotate the pipe to some extent generally at least one-half rotation.

In many well equipping operations, rotation of the pipe to couple it to another structure may be impractical or impossible for various reasons. Accordingly, it is a principal object of the present invention to provide a form of bayonet-type coupling or latch which is actuated entirely by longitudinal movements of the pipe string to automatically effect latching or coupling of the pipe string with the structure to which it is coupled.

It is a further object of this invention to provide an automatic bayonet-type latch of the character described which is both engageable and releasable in response solely to longitudinal movements of the pipe string.

In accordance with the present invention, the automatic latch comprises a latch body secured by means of a swivel connection to the pipe string and insertable in a socket in the structure to which it is to be coupled. The swivel-connected latch body carries cams which are en- .gageable with cam followers mounted in the wall of the socket, the cams being constructed and arranged to cause rotation of the body through engagement with the cam followers to a latching position, the cam followers functioning in cooperation with the cams as latch elements to secure the pipe in place in the socket.

The cam shapes employed are designed to cooperate with the cam followers upon a first downward movement of the pipe string to cause rotation of the latch body in a direction to place a latching recess in position to receive the follower in response to a subsequent first upward movement of the pipe string. A second cam, arranged in sequence with the first cam, is positioned to be engaged by the follower upon a second downward movement of the pipe string to further rotate the latch body to a position which will place the follower opposite a longitudinal opening through which the cam follower will pass in response to a second upward movement of the pipe string to effect release of the latch.

In accordance with this invention, therefore, a cam arrangement is provided by means of which the pipe string 3,Zll,4 79 Patented Oct. 12, 1965 ice may be latched to another body by a first series of movements, comprising successive downward and upward longitudinal movements of the pipe string and which, to effect release of the latch, is accomplished by a subsequent second series of downward and upward longitudinal movements of the pipe string.

Other and more specific objects and advantages of this invention will become apparent from the following de tailed description when read in conjunction with the accompanying drawing which illustrates one useful embodiment in accordance with this invention.

In the drawing, FIG. 1 is a generally schematic view showing a well equipped with two pipe strings and other well equipment employing a latching device in accordance with this invention;

FIG. 2 is a cross-sectional view taken generally along line 22 of FIG. 1;

FIG. 3 is a longitudinal sectional view on an enlarged scale of the automatic latch, in accordance with one embodiment of this invention; and

FIG. 4 is a linear development of the cam element of the latch.

FIG. 1 illustrates a well bore W lined with a conventional casing C equipped at its upper end with a casinghead H. There is shown positioned in casing C a generally conventional dual-string well packer, designated generally by the letter F, for packing oif the well bore about two parallel strings of tubing T and T which are suitably supported in casinghead H by means of a conventional tubing hanger G. Tubing T represents a string of tubing fitted with a series of conventional gas lift valves V secured to the exterior thereof and projecting radially therefrom, as seen in FIG. 2, so as to make it impractical or impossible to rotate tubing string T in order to secure it to packer P by conventional coupling devices, such tubing string T must normally be run after tubing string T and the packer is already in place in the well. The lower end of tubing string T carries an automatic latch in accordance with this invention, designated generally by the numeral 10, and indicated in broken lines in FIG. 1 as positioned in a socket S provided in the body B of the packer. As seen in FIG. 3, socket S communicates at its lower end with a co-axial passage K which extends through the packer, the bottom of socket S being downwardly tapered to form a seat L.

Referring to FIGS. 3 and 4, latching device 10 comprises a cylindrical latching sleeve 15 dimensioned to slide freely into the bore of socket S and desirably having its lower end chamfered at 16 to complement the taper of seat L. The upper end of latching sleeve 15 is adapted to be secured to the lower end of tubing string T by means of a swivel connection, designated generally by the numeral 17. The latter includes a tubular body 18 externally threaded at its upper end at 18a for threaded reception in the lower end of tubing string T Body 18 is provided at its lower end with a radial enlargement 19 which is slida'bly receivable in a socket 20 provided in the upper end of sleeve 15 and defined by a bottom 21 and an upwardly extending cylindrical flange 22.. Enlargement 19 defines :an upwardly facing annular shoulder 23 forming the bottom of an annular recess defined between the exterior of body 18 and the inner wall of flange 22. The portion of the latter above shoulder 23 is internally threaded at 23a to receive an externally threaded tubular swivel bushing 24 having a bore 25 through which body 18 extends. The upper end of bushing 24 is provided with .a radially enlarged head 26 which extends outwardly over the upper end of extension 22, and the lower end of bushing 24 defines an internal shoulder in sleeve 15 which is adapted to rest on shoulder 23. It will be seen from the described arrangement that when bushing 24 is in place, as illustrated in FIG. 3, .a freely rotatable swivel connection will be provided between tubing string T and latching sleeve 15.

An annular seal packing 30 is disposed about the exterior of body 18 between the lower end of tubing string T and head 26 of the swivel bushing. Metal gland rings 31--31 are disposed between opposite ends of seal packing 30 and the adjacent ends of the tubing string and head 26 of the swivel bushing. Packing 30 is adapted to form a slida'ble seal with the wall of socket S when the latching device is inserted into the socket.

A pair of cylindrical pins 35-35 are suitably mounted in the wall of socket S at diametrically spaced points to project radially a short distance into the bore of the socket. These pins, for the purposes of this description, are termed the cam followers and are adapted to cooperate with an upper cylindrical guide cam member 36 and lower latching cams 3737 formed, or suitably mounted in vertically spaced relation on the exterior surface of latching sleeve 15.

Guide cam member 36, while formed as a continuous member, comprises two identical cams 36a-36a, each extending about 180 of the circumference of latching sleeve 15 and disposed in continuous end-to-end relation, each of the guide cams 36a being positioned to cooperate with one of the followers 35 and with one of the latching cams 37, as will appear subsequently. Latching cams 37 are identical in size and configuration :and are disposed about the exterior of sleeve 15 in symmetrical relation with respect to their related guide cams 36a. The spaces between the opposed guide surfaces of guide cams 36a and their related latching cam-s 37 define generally circumferenti-ally extending guideways 60 on opposite sides of sleeve 15, each having an entrance slot :61 and an outlet slot 62 at its opposite ends.

Each of the guide cams 36a comprises two circumferentially spaced apart, downwardly projecting lobes 38 and 39. Lobe 38 is defined by vertically extending, generally parallel forward and back faces 40 and 41, respectively, connected together by an end face 42 which "slopes rearwardly or in the anti-clockwise direction. As used herein forward refers to the left-hand or clockwise direction and rearward to the right-hand or anticlockwise direction, as viewed in FIG. 4. An angular guide face 43 slopes upwardly and forwardly from face 40 and connects with the rear face 44 of lobe 39, the juncture or angle between faces 43 and 44 defining an arcuate recess 45 having a radius corresponding generally to that of followers 35. Rear face 44 extends downwardly and at a slight forward slope to a juncture with forward face 46 of lobe 39, the juncture of these faces being defined by the rounded nose 47. Forward face 46 slopes upwardly and forwardly from nose'47 to a juncture with the upper end of rear face 41 of the second lobe 38, the juncture between these faces defining an arcuate recess 48 having a radius corresponding generally to that of followers 35.

Each of the latching cams 37 extends over an arcuate length of the surface of sleeve 15 somewhat less than 180. As viewed in FIG. 4, each cam 37 is defined by a lower cam face 50 which slopes upwardly and rearwardly in the anti-clockwise direction direction, merging at its rearward extremity with a short vertically extending face 51 which is disposed generally parallel to and spaced from forward face 40 of cam lobe 38, to define therebetween a vertically extending entrance slot 61 open at its lower end and having a width to freely accommodate a follower 35. Face 51 is connected by a rounded nose 53 with a downwardly and forwardly sloping guide face 54. Cam 37 is so positioned and dimensioned with relation to its related cam 36a that its rearward extremity defined by nose 53 will extend slightly rearwardly of a vertical line passing through the center of recess 45. Guide face 54 merges with a short upwardly and forwardly inclined face 55. The angle between faces 54 and 55 is defined by an arcuate recess 56 having a radius substantially equal to that of followers 35. Recess 56 is the latching recess of the latching device. The length of face 54 is made such that the center of latching recess 56 will be slightly forward of nose 47 of lobe 39. The upper end of face 55 connects through a rounded surface 57 with an upper face 58 which extends downwardly and forwardly generally parallel to lower cam face 50, and is connected to the latter by a downwardly and rearwardly sloping end face 59. Upper cam face 58 has a length to extend forwardly from a point rearwardly of the center of recess 48 beneath and generally parallel to end face 42 of cam lobe 33, being spaced therefrom to define outlet slot 62 having a width to freely accommodate followers 35 and opening downwardly between cams 37. At noted, entrance and outlet slots 61 and 62 define the opposite ends of guideway 60 which is traversed by one of the followers 35 during engagement and release of the automatic latch, as will be described hereinafter.

Operation of the device is as follows, the description being directed to the relative movement of one guideway relative to one follower, the other pair of latch elements operating in the identical manner. Tubing string T having an automatic latch 10 connected to its lower end is inserted through the well bore and the latch inserted into socket S. As latching sleeve 15 enters the socket, each follower 35 will be engaged by a latching cam 37. The initial points of contact may be either on face 50 or face 59 of latching cam 37. In either event, the slopes of these faces will cause sleeve 15 to rotate in a direction which will align the entrance slot 61 with a follower 35, is illustrated in FIG. 4. Continuing downward movement of the latching sleeve will, in effect, cause follower 35 to move through entrance slot 61 following a path such as indicated in broken lines (FIG. 4), and in the direction indicated by the arrows on the broken line. Initially, the cam follower will pass upwardly through entrance slot 61 striking guide face 43 whose pitch will cause latching sleeve 15 to rotate in the anti-clockwise direction until follower 35 enters recess 45, a position indicated by the legend Pos. 1". Upon entrance of follower 35 into recess 45, downward movement of the tubing string will be stopped, thereupon an upward pull will be taken on the tubing string with the result that the latching sleeve will be drawn upwardly relative to follower 35, producing the relative downward movement of the latter until it strikes face 54 of the latching cam. The pitch of the latter will produce further anti-clockwise rotation of latching sleeve 15 until follower 35 is seated in latching recess 56. Attainment of this position, indicated as Pos. 2, will stop further upward movement of the tubing string and will thereby provide a signal at the surface that the follower is seated in the latching recess. Thereupon, tubing string T will be secured in tension in tubing hanger G, thereby accomplishing the coupling of the tubing string to the packer. It will be seen that by the succession first of a downward movement followed by an upward movement of the tubing string, latching will be effected.

To release the latch, it is only necessary to release the tubing string T from hanger G and lower the tubing string. As latching sleeve 15 is correspondingly lowered, relative upward movement of follower 35 will occur from latching recess 56 to engage guide face 46 forwardly of nose 47 and further downward movement of the tubing string will act through the engagement of face 46 with follower 35 to rotate latching sleeve 15 in the anti-clockwise direction until follower 35 is seated in recess 48, this position being designated as Pos. 3. In this position it will be seen that follower 35 will be disposed vertically above guide face 58 of latching cam 37. Also, it will be evident that entrance of follower 35 into recess 48 will stop further downward movement of the tubing string and will provide a signal at the surface that position 3 has been attained. Thereupon, upward movement applied to the tubing string will raise the latching sleeve relative to follower 35 until the latter engages guide face 58, causing further anti-clockwise rotation of the latching sleeve and allowing follower 35 to pass out of the guideway through outlet slot 62. In thus effecting release of the latch, it will be seen that this is accomplished by a second sequence of first a downward movement of the tubing string followed by an upward movement thereof.

It will be clear that by the arrangement and form of the cams illustrated, it will be immaterial at what position latching sleeve enters socket S, since upon engagement of any of the surfaces 50 and 59 with the cam followers, the latching sleeve will be rotated to a position aligning the entrance slots 61 with the cam followers, so that the latching and unlatching previously described will be accomplished automatically and entirely by longitudinal reciprocation of tubing string T It will be evident that while the automatic latch previously described has been described for use in coupling the lower end of a tubing string to a down-well structure, the form of latch described may be used to effect coupling between any pair of bodies, one of which is provided with a cylindrical socket.

While the illustrative embodiment has shown the latching sleeve, by reason of its swivel connection to tubing string T as being rotatable relative to the latching pins 35, it will be readily seen that the same automatic latching action may be effected by mounting latching pins 35 in any suitable and known manner so as to rotate or swivel freely in socket S, latching sleeve 15 being stationarily secured to tubing string T Both arrangements are contemplated in accordance in accordance with this invention.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment with the scope of the appended claims, but without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent is:

1. An automatic bayonet-type latch for releasably connecting two bodies, one of said bodies having a cylindrical socket, comprising, a cylindrical latch member projecting radially into said socket, a cylindrical sleeve member coaxially insertable into said socket, swivel means forming a freely rotatable connection between said sleeve member and the other of said bodies, an annular seal packing carried by the swivel means above the sleeve member for sealing with the wall of said socket, a guideway for said latch member defined by spaced upper and lower walls extending generally circumferentially about a portion of said sleeve member and having its opposite ends opening toward the lower end of said sleeve member, said lower wall having a latching recess between the ends thereof for receiving said latch member, said walls having contours cooperable with said latch member in response to sequential solely longitudinal reciprocations of one of said bodies relative to the other to rotate said sleeve member between positions successively moving said latching recess into and out of latching engagement with said latch member.

2. An automatic bayonet-type latch according to claim 1 wherein said one of said bodies is a down-well structure, and said other of said bodies is a well pipe.

3. An automatic bayonet-type latch for releasably connecting two bodies, one of said bodies having a cylindrical socket, comprising, a cylindrical latch member projecting radially into said socket, a cylindrical sleeve member coaxially insertable into said socket, swivel means forming a freely rotatable connection between said sleeve member and the other of said bodies, an annular seal packing carried by the swivel means above the sleeve member for sealing with the wall of said socket, a guideway for said latch member defined by spaced upper and lower walls extending generally circumferentially about a portion of said sleeve member and having its opposite ends opening toward the lower end of said sleeve member, said lower wall having a latching recess between the ends thereof for receiving said latch member, said walls having contours cooperable with said latch member in response to a first pair of sequential solely longitudinal reciprocations of one of said bodies relative to the latch member to rotate said sleeve member to positions relative to the other operable to guide the latter through one end of said guideway into said latching recess and by a subsequent second pair of said sequential solely longitudinal recipro cations out of said latching recess and out of the other end of said guideway.

4. An automatic bayonet-type latch according to claim 3 wherein said one of said bodies is a down-well structure, and said other of said bodies is a well pipe.

5. An automatic bayonet-type latch for releasably connecting two bodies, one of said bodies having a cylindrical socket, and the other of said bodies having a tubular end portion, comprising, a cylindrical latch member projecting radially into said socket, a cylindrical sleeve member mounted on said tubular end portion coaxially insertable into said socket, swivel means forming a freely rotatable connection between said sleeve member and said tubular end portion, said swivel means comprising cooperably inter-engaged annular shoulder means on said tubular end portion and in said sleeve member, a guideway for said latch member defined by spaced upper and lower walls extending generally circumferentially about a portion of said sleeve member and having its opposite ends opening to the lower end of said sleeve member, said lower wall having a latching recess for receiving said latch member, said walls having contours cooperable with said latch member in response to a first pair of sequential solely longitudinal reciprocations of one of said bodies relative to the other to rotate said sleeve member to a position effecting latching engagement between said latching recess and said latch members, and by a subsequent second pair of sequential solely longitudinal reciprocations to rotate said sleeve member to a position releasing said latching engagement.

6. An automatic bayonet-type latch for releasably connecting a well pipe string to a down-well structure having a cylindrical socket, comprising, a pair of cylindrical latch members projecting radially into said socket from diametrically opposite sides thereof, a cylindrical sleeve member coaXially insertable into said socket, swivel means forming a freely rotatable connection between said sleeve member and the lower end of said pipe string, an annular seal packing carried by the swivel means-above the sleeve member for sealing engagement with the wall of said socket, guideways for said latch members defined by spaced upper and lower walls and each extending generally circumferentially about opposite portions of the exterior of said sleeve member, said guideways having their opposite ends opening toward the lower end of said sleeve member, said lower walls having latching recesses for receiving the respective latch members, said walls having contours cooperably engageable with said latch members in response to a first pair of sequential solely longitudinal reciprocations of the pipe string relative to the latch member to rotate said sleeve member to positions relative to the latch members operable to guide the latter through one end of the respective guideways into said latching recesses and by .a subsequent pair of sequential solely longitudinal reciprocations out of said latching recesses and out of the other end of the respective guideways.

7. An automatic bayonet-type latch according to claim 6 wherein said swivel means comprises, a tubular body having its upper end fixedly secured to the pipe string and its lower end coaxially inserted in the upper end of said sleeve member, an external annular shoulder means carried by the lower end of said body, and an internal annular shoulder means in the upper end of said sleeve member disposed on top of said external shoulder in rotatable engagement therewith.

References Cited by the Examiner UNITED STATES PATENTS Miller 28561 MacKenzie 285-280 Coberly 285-361 Baker 166123 Muse 285-396 Evans 166181 Fahrenwald 285-402 Le Bus 285-361 Crowe 285-18 CARL W. TOMLIN, Primary Examiner. 

1. AN AUTOMATIC BAYONET-TYPE LATCH FOR RELEASABLY CONNECTING TWO BODIES, ONE OF SAID BODIES HAVING A CYLINDRICAL SOCKET COMPRISING, A CYLINDRICAL LATCH MEMBER PROJECTING RADIALLY INTO SAID SOCKET, A CYLINDRICAL SLEEVE MEMBER COAXIALLY INSERTABLE INTO SAID SOCKET, SWIVEL MEANS FORMING A FREELY ROTATABLE CONNECTION BETWEEN SAID SLEEVE MEMBER AND THE OTHER OF SAID BODIES, AN ANNULAR SEAL PACKING CARRIED BY THE SWIVEL MEANS ABOVE THE SLEEVE MEMBER FOR SEALING WITH THE WALL OF SAID SOCKET, A GUIDEWAY FOR SAID LATCH MEMBER DEFEINED BY SPACED UPPER AND LOWER WALLS EXTENDING GENERALLY CIRCUMFERENTIALLY ABOUT A PORTION OF SAID SLEEVE MEMBER AND HAVING ITS OPPOSITE ENDS OPENING TOWARD THE LOWER END OF SAID SLEEVE MEMBER, SAID LOWER WALL HAVING A LATCHING RECESS BETWEEN THE ENDS THEREOF FOR RECEIVING SAID LATCH MEMBER, SAID WALLS HAVING CONTOURS COOPERABLE WITH SAID LATCH MEMBER IN RESPONSE TO SEQUENTIAL SOLELY LONGITUDINAL RECIPROCATIONS OF ONE OF SAID BODIES RELATIVE TO THE OTHER TO ROTATE SAID SLEEVE MEMBER BETWEEN POSITIONS SUCCESSIVELY MOVING SAID LATCHING RECESS INTO AND OUT OF LATCHING ENGAGEMENT WITH SAID LATCH MEMBER. 